Process for the catalytic hydrogenolysis of p-substituted benzaldehyde-dimethylacetals to produce the corresponding benzyl methyl ether derivatives

Abstract

Disclosed is a process for catalytic hydrogenolysis of p-substituted benzaldehyde-dialkyl-acetals of the general formula ##STR1## in which R is an alkyl group, an unsubstituted or substituted aryl group or an unsubstituted or substituted aralkyl group, by means of a catalyst system composed of cobalt carbonyl and at least one nitrogen-containing heterocyclic compound, such as pyridine, pyrrole, pyrrolidone or piperidine and a hydrogen/carbon monoxide mixture to give the corresponding p-substituted benzyl alkyl ether derivatives.

What is claimed is: 
     
       1. A process for the catalytic hydrogenolysis of p-substituted benzaldehyde-dialkylacetals to produce the corresponding p-substituted benzyl alkyl ether derivatives, comprising the step of: hydrogenolyzing a p-substituted benzaldehyde-dialkylacetal compound selected from the group consisting of 4-methoxy-benzaldehyde-dimethylacetal, 4-phenoxy-benzaldehyde-dimethylacetal, and 4,4'-diphenyl ether-dialdehydebis-dimethylacetal, in the presence of a catalyst system comprising a cobalt carbonyl and at least one heterocyclic compound containing at least one heterocyclic nitrogen atom selected from the group consisting of pyridine, pyrrole, pyrrolidone and piperidine.   
     
     
       2. A process as claimed in claim 1, wherein the molar ratio of said nitrogen-containing heterocyclic compound to said cobalt carbonyl is in the range of from 1:1 to 16:1. 
     
     
       3. A process as claimed in claim 2, wherein the concentration of said cobalt carbonyl is between about 0.5 and 5 mole % per mole of dimethylacetal group. 
     
     
       4. A process as claimed in claim 3, wherein the proportion of said cobalt carbonyl is from about 0.5 to 5 mole % and the proportion of said nitrogen-containing heterocyclic compound is from about 0.5 to 20 mole %, each relative to 1 mole of dimethylacetal group, and the carbon monoxide partial pressure is from about 20 to 60 bar. 
     
     
       5. A process as claimed in claim 4, wherein the proportion of said cobalt carbonyl is from about 0.75 to 2 mole % and the proportion of said nitrogen-containing heterocyclic compound is from about 1.5 to 8 mole %, each relative to 1 mole of dimethylacetal group, and the carbon monoxide partial pressure is from about 30 to 50 bar.